Louis Taillefer

Louis Taillefer
Université de Sherbrooke | UdeS · Department of Physics

PhD, University of Cambridge

About

436
Publications
41,872
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18,886
Citations
Citations since 2017
65 Research Items
6425 Citations
201720182019202020212022202302004006008001,0001,200
201720182019202020212022202302004006008001,0001,200
201720182019202020212022202302004006008001,0001,200
201720182019202020212022202302004006008001,0001,200
Additional affiliations
July 1998 - present
Canadian Institute For Advanced Research
Position
  • Director, Quantum Materials Program

Publications

Publications (436)
Preprint
The 2D layered insulator $\alpha$-RuCl$_3$ is a candidate material for a quantum spin-liquid state, which may be realized when a magnetic field suppresses the antiferromagnetic order present at low temperature. Oscillations in the field dependence of the thermal conductivity, observed for an in-plane magnetic field $B$ up to a critical field $B^{\s...
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We report thermal conductivity measurements on single crystals of herbertsmithite, over a wide range of temperatures (0.05-120 K) in magnetic fields up to 15 T. We also report measurements of the thermal Hall effect, found to be vanishingly small. At high temperatures, in the paramagnetic regime, the thermal conductivity has a negligible field depe...
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In various so-called strange metals, electrons undergo Planckian dissipation1,2, a strong and anomalous scattering that grows linearly with temperature3, in contrast to the quadratic temperature dependence expected from the standard theory of metals. In some cuprates4,5 and pnictides6, a linear dependence of resistivity on a magnetic field has also...
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Phonons are known to generate a thermal Hall effect in certain insulators, including oxides with rare-earth impurities, quantum paraelectrics, multiferroic materials, and cuprate Mott insulators. In each case, a special feature of the material is presumed relevant for the underlying mechanism that confers chirality to phonons in a magnetic field. A...
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Electronic nematicity is the spontaneous loss of rotational symmetry in a metal, without breaking translational symmetry. In the cuprate superconductors, there is experimental evidence for nematicity, but its origin remains unclear. Here we investigate the onset of nematicity in the transport of charge by means of electric and thermoelectric measur...
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Materials tuned to a quantum critical point display universal scaling properties as a function of temperature $T$ and frequency $\omega$. A long-standing puzzle in the quantum critical behavior of cuprate superconductors has been the observed power-law dependence of optical conductivity with an exponent smaller than one, to be contrasted with the $...
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Low-temperature (down to $\sim$ 50 mK) thermal conductivity measurements with the heat flow direction along the inter-plane tetragonal $c$-axis, $\kappa_c$, were used to study the superconducting state of heavy fermion CeIrIn$_5$. Measurements were performed in the magnetic fields both parallel to the heat flow direction, $H\parallel c$, and transv...
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Measurements of the thermal Hall conductivity in hole-doped cuprates have shown that phonons acquire chirality in a magnetic field both in the pseudogap phase and in the Mott insulator state. The microscopic mechanism at play is still unclear. A number of theoretical proposals are being considered including skew scattering of phonons by various def...
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Full-text available
We report measurements of the Seebeck effect in both the ab plane (S_{a}) and along the c axis (S_{c}) of the cuprate superconductor La_{1.6-x}Nd_{0.4}Sr_{x}CuO_{4} (Nd-LSCO), performed in magnetic fields large enough to suppress superconductivity down to low temperature. We use the Seebeck coefficient as a probe of the particle-hole asymmetry of t...
Preprint
Measurements of the thermal Hall conductivity in hole-doped cuprates have shown that phonons acquire chirality in a magnetic field, both in the pseudogap phase and in the Mott insulator state. The microscopic mechanism at play is still unclear. A number of theoretical proposals are being considered, including skew scattering of phonons by various d...
Preprint
The material $\alpha$-RuCl$_3$ has been the subject of intense scrutiny as a potential Kitaev quantum spin liquid, predicted to display Majorana fermions as low energy excitations. In practice, $\alpha$-RuCl$_3$ undergoes a transition to a state with antiferromagnetic order below a temperature $T_{\rm N}$ $\approx$ 7 K, but this order can be suppre...
Preprint
Full-text available
Phonons are known to generate a thermal Hall effect in certain insulators, including oxides with rare-earth impurities, quantum paraelectrics, multiferroic materials and cuprate Mott insulators. In each case, a special feature of the material is presumed relevant for the underlying mechanism that confers chirality to phonons in a magnetic field. Th...
Article
Full-text available
A variety of ‘strange metals’ exhibit resistivity that decreases linearly with temperature as the temperature decreases to zero1–3, in contrast to conventional metals where resistivity decreases quadratically with temperature. This linear-in-temperature resistivity has been attributed to charge carriers scattering at a rate given by ħ/τ = αkBT, whe...
Preprint
We report measurements of the Seebeck effect in both the $ab$ plane ($S_{\rm a}$) and along the $c$ axis ($S_{\rm c}$) of the cuprate superconductor La$_{1.6-x}$Nd$_{0.4}$Sr$_{x}$CuO$_4$ (Nd-LSCO), performed in magnetic fields large enough to suppress superconductivity down to low temperature. We use the Seebeck coefficient as a probe of the partic...
Article
The specific heat C of the cuprate superconductors La2−xSrxCuO4 and Bi2+ySr2−x−yLaxCuO6+δ was measured at low temperatures (down to 0.5 K) for dopings p close to p★, the critical doping for the onset of the pseudogap phase. A magnetic field up to 35 T was applied to suppress superconductivity, giving direct access to the normal state at low tempera...
Article
The specific heat C of the cuprate superconductors La2−xSrxCuO4 and Bi2+ySr2−x−yLaxCuO6+δ was measured at low temperatures (down to 0.5 K) for dopings p close to p★, the critical doping for the onset of the pseudogap phase. A magnetic field up to 35 T was applied to suppress superconductivity, giving direct access to the normal state at low tempera...
Article
Full-text available
We report thermopower measurements under hydrostatic pressure on the cuprate superconductor La1.6−xNd0.4SrxCuO4 (Nd-LSCO), at low temperature in the normal state accessed by suppressing superconductivity with a magnetic field up to H=31T. Using an ac thermopower measurement technique suitable for high pressure and high field, we track the pressure...
Article
The Seebeck coefficient (thermopower) S of the cuprate superconductor La 1.6−x Nd 0.4 Sr x CuO 4 was measured across its doping phase diagram (from p = 0.12 to p = 0.25), at various temperatures down to T 2 K, in the normal state accessed by suppressing superconductivity with a magnetic field up to H = 37.5 T. The magnitude of S/T in the T = 0 limi...
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Full-text available
In recent years, the notion of Quantum Materials has emerged as a powerful unifying concept across diverse fields of science and engineering, from condensed-matter and cold atom physics to materials science and quantum computing. Beyond traditional quantum materials such as unconventional superconductors, heavy fermions, and multiferroics, the fiel...
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Full-text available
The quasi-two-dimensional metal Sr2RuO4 is one of the best characterized unconventional superconductors, yet the nature of its superconducting order parameter is still under debate1–3. This information is crucial to determine the pairing mechanism of Cooper pairs. Here we use ultrasound velocity to probe the superconducting state of Sr2RuO4. This t...
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Full-text available
The specific heat $C$ of the cuprate superconductors La$_{2-x}$Sr$_x$CuO$_4$ and Bi$_{2+y}$Sr$_{2-x-y}$La$_x$CuO$_{6+\delta}$ was measured at low temperature (down to $0.5~{\rm K}$), for dopings $p$ close to $p^\star$, the critical doping for the onset of the pseudogap phase. A magnetic field up to $35~{\rm T}$ was applied to suppress superconducti...
Article
Full-text available
In recent years, the notion of "Quantum Materials" has emerged as a powerful unifying concept across diverse fields of science and engineering, from condensed-matter and cold-atom physics to materials science and quantum computing. Beyond traditional quantum materials such as unconventional superconductors, heavy fermions, and multiferroics, the fi...
Article
Full-text available
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Preprint
Full-text available
We report thermopower measurements under hydrostatic pressure on the cuprate superconductor La$_{1.6-x}$Nd$_{0.4}$Sr$_x$CuO$_4$ (Nd-LSCO), at low-temperature in the normal state accessed by suppressing superconductivity with a magnetic field up to $H = 31$ T. Using a newly developed AC thermopower measurement technique suitable for high pressure an...
Preprint
Full-text available
The Seebeck coefficient (thermopower) $S$ of the cuprate superconductor La$_{1.6-x}$Nd$_{0.4}$Sr$_x$CuO$_4$ was measured across its doping phase diagram (from $p = 0.12$ to $p = 0.25$), at various temperatures down to $T \simeq 2$ K, in the normal state accessed by suppressing superconductivity with a magnetic field up to $H = 37.5$ T. The magnitud...
Preprint
Full-text available
A variety of "strange metals" exhibit resistivity that is perfectly linear in temperature as $T\rightarrow 0$, in contrast with conventional metals where resistivity increases as $T^2$. This $T$-linear resistivity has been attributed to a scattering rate $1/\tau$ of the charge carriers given by $\hbar/\tau=\alpha k_{\rm B} T$, with $\alpha$ of orde...
Article
Full-text available
The nature of the pseudogap phase of cuprates remains a major puzzle1,2. One of its signatures is a large negative thermal Hall conductivity3, whose origin is as yet unknown. This is observed even in the undoped Mott insulator La2CuO4, in which the charge carriers are localized and therefore cannot be responsible. Here, we show that the thermal Hal...
Article
Full-text available
The heat carriers responsible for the unexpectedly large thermal Hall conductivity of the cuprate Mott insulator La2CuO4 were recently shown to be phonons. However, the mechanism by which phonons in cuprates acquire chirality in a magnetic field is still unknown. Here, we report a similar thermal Hall conductivity in two cuprate Mott insulators wit...
Article
One branch of the La-214 family of cuprate superconductors, La1.6−xNd0.4SrxCuO4 (Nd-LSCO), has been of significant and sustained interest, in large part because it displays the full complexity of the phase diagram for canonical hole-doped, high TC superconductivity, while also displaying relatively low superconducting critical temperatures. The low...
Article
The elastic modulus c44 of a single crystal of the Weyl semimetal TaAs was investigated by measuring relative changes in the sound velocity under application of a magnetic field up to 10 T. Using an ultrasonic pulsed-echo technique, we studied the shear response of the crystal when the angle between the sound wave propagation and the magnetic field...
Preprint
Full-text available
Four transport coefficients of the cuprate superconductor Bi$_2$Sr$_{2-x}$La$_x$CuO$_{6+\delta}$ were measured in the normal state down to low temperature, achieved by applying a magnetic field (up to 66T) large enough to fully suppress superconductivity. The electrical resistivity, Hall coefficient, thermal conductivity and Seebeck coefficient wer...
Preprint
Full-text available
One branch of the La-214 family of cuprate superconductors, La1.6-xNd0.4SrxCuO4 (Nd-LSCO), has been of significant and sustained interest, in large part because it displays the full complexity of the phase diagram for canonical hole-doped, high Tc superconductivity, while also displaying relatively low superconducting critical temperatures. The low...
Article
We study Shubnikov–de Haas oscillations in single crystals of TaAs and find a previously undetected two-dimensional quantum oscillation that does not belong to the bulk Fermi surface. We cannot find an impurity phase consistent with our observations, and extensive diffraction measurements have not shown the presence of known impurity phases. We con...
Article
Full-text available
The specific heat C of the single-layer cuprate superconductor HgBa2CuO4+δ was measured in an underdoped crystal with Tc=72 K at temperatures down to 2 K in magnetic fields up to 35 T, a field large enough to suppress superconductivity at that doping (p≃0.09). In the normal state at H=35 T, a residual linear term of magnitude γ=12±2 mJ/K2mol is obs...
Preprint
Full-text available
The heat carriers responsible for the unexpectedly large thermal Hall conductivity of the cuprate Mott insulator La$_2$CuO$_4$ were recently shown to be phonons. However, the mechanism by which phonons in cuprates acquire chirality in a magnetic field is still unknown. Here, we report a similar thermal Hall conductivity in two cuprate Mott insulato...
Preprint
Full-text available
The specific heat $C$ of the single-layer cuprate superconductor HgBa$_2$CuO$_{4 + \delta}$ was measured in an underdoped crystal with $T_{\rm c} = 72$ K at temperatures down to $2$ K in magnetic fields up to $35$ T, a field large enough to suppress superconductivity at that doping ($p \simeq 0.09$). In the normal state at $H = 35$ T, a residual li...
Preprint
Full-text available
The nature of the pseudogap phase remains a major barrier to our understanding of cuprate high-temperature superconductivity. Whether or not this metallic phase is defined by any of the reported broken symmetries, the topology of its Fermi surface remains a fundamental open question. Here we use angle-dependent magnetoresistance (ADMR) to measure t...
Preprint
The nature of the pseudogap phase of cuprates remains a major puzzle. One of its new signatures is a large negative thermal Hall conductivity $\kappa_{\rm xy}$, which appears for dopings $p$ below the pseudogap critical doping $p^*$, but whose origin is as yet unknown. Because this large $\kappa_{\rm xy}$ is observed even in the undoped Mott insula...
Preprint
The quasi-2D metal Sr$_2$RuO$_4$ is one of the best characterized unconventional superconductors, yet the nature of its superconducting order parameter is still highly debated. Here we use ultrasound velocity to probe the superconducting state of Sr$_2$RuO$_4$. We observe a sharp jump in the shear elastic constant $c_{66}$ as the temperature is rai...
Article
Full-text available
The thermal conductivity κ of the quasi-2D organic spin-liquid candidate EtMe_{3}Sb[Pd(dmit)_{2}]_{2} (dmit-131) was measured at low temperatures, down to 0.07 K. We observe a vanishingly small residual linear term κ_{0}/T, in κ/T vs T as T→0. This shows that the low-energy excitations responsible for the sizable residual linear term γ in the speci...
Preprint
A key unexplained feature of cuprate superconductors is the upturn in their normal state electrical resistivity $\rho(T)$ seen at low temperature inside the pseudogap phase. We examined this issue via measurements of the thermal conductivity $\kappa(T)$ down to 50 mK and in fields up to 17 T on the cuprate La$_{2-x}$Sr$_x$CuO$_4$ at dopings $p = 0....
Preprint
The elastic modulus C44 of a Weyl semi-metal TaAs single crystal was investigated by measuring relative changes in the sound velocity under application of a magnetic field up to 10 T. Using an ultrasonic pulsed-echo technique, we studied the shear response of the crystal when the angle between the sound wave propagation and the magnetic field is ch...
Article
Full-text available
The nature of the pseudogap phase of the copper oxides (‘cuprates’) remains a puzzle. Although there are indications that this phase breaks various symmetries, there is no consensus on its fundamental nature¹. Fermi-surface, transport and thermodynamic signatures of the pseudogap phase are reminiscent of a transition into a phase with antiferromagn...
Preprint
The thermal conductivity $\kappa$ of the quasi-2D organic spin-liquid candidate EtMe3Sb[Pd(dmit)2]2 (dmit-131) was measured at low temperatures, down to 0.07 K. We observe a vanishingly small residual linear term $\kappa_0$/T, in $\kappa$/T vs T as T $\rightarrow$ 0. This shows that the low-energy excitations responsible for the sizeable residual l...
Article
Cuprates exhibit exceptionally strong superconductivity.To understand why, it is essential to elucidate the nature of the electronic interactions that cause pairing. Superconductivity occurs on the backdrop of several underlying electronic phases, including a doped Mott insulator at low doping, a strange metal at high doping, and an enigmatic pseud...
Article
Full-text available
The three central phenomena of cuprate superconductors are linked by a common doping $p^{\star}$, where the enigmatic pseudogap phase ends, around which the superconducting phase forms a dome, and at which the resistivity exhibits an anomalous linear dependence on temperature as $T \to 0$. However, the fundamental nature of $p^{\star}$ remains uncl...
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The perfectly linear temperature dependence of the electrical resistivity observed as T → 0 in a variety of metals close to a quantum critical point1–4 is a major puzzle of condensed-matter physics⁵. Here we show that T-linear resistivity as T → 0 is a generic property of cuprates, associated with a universal scattering rate. We measured the low-te...
Preprint
Full-text available
The nature of the pseudogap phase of cuprates remains a major puzzle. Although there are indications that this phase breaks various symmetries, there is no consensus on its fundamental nature. Although Fermi-surface, transport and thermodynamic signatures of the pseudogap phase are reminiscent of a transition into a phase with antiferromagnetic ord...
Preprint
Full-text available
A signature property of Weyl semimetals is the existence of topologically protected surface states - arcs in momentum space that connect Weyl points in the bulk. However, the presence of bulks states makes detection of surface contributions to the transport challenging. Here we present a magnetoresistance study of high-quality samples of the protot...
Article
We present a detailed study of the temperature (T) and magnetic field (H) dependence of the electronic density of states (DOS) at the Fermi level, as deduced from specific heat and Knight shift measurements in underdoped YBa2Cu3Oy. We find that the DOS becomes field independent above a characteristic field HDOS, and that the HDOS(T) line displays a...
Article
Full-text available
The thermal conductivity κ of the cuprate superconductor La_{1.6-x}Nd_{0.4}Sr_{x}CuO_{4} was measured down to 50 mK in seven crystals with doping from p=0.12 to p=0.24, both in the superconducting state and in the magnetic field-induced normal state. We obtain the electronic residual linear term κ_{0}/T as T→0 across the pseudogap critical point p^...
Article
Cuprate superconductors have a universal tendency to form charge density-wave (CDW) order which competes with superconductivity and is strongest at a doping p≃0.12. Here we show that in the archetypal cuprate YBa2Cu3Oy (YBCO) pressure suppresses charge order but does not affect the pseudogap phase. This is based on transport measurements under pres...
Preprint
Cuprates exhibit exceptionally strong superconductivity. To understand why, it is essential to elucidate the nature of the electronic interactions that cause pairing. Superconductivity occurs on the backdrop of several underlying electronic phases, including a doped Mott insulator at low doping, a strange metal at high doping, and an enigmatic pseu...
Preprint
We present a detailed study of the temperature (T) and magnetic field (H) dependence of the electronic density of states (DOS) at the Fermi level, as deduced from specific heat and Knight shift measurements in underdoped YBa2Cu3Oy. We find that the DOS becomes field-independent above a characteristic field H_{DOS} and that the H_{DOS}(T) line displ...
Preprint
Full-text available
The thermal conductivity $\kappa$ of the cuprate superconductor La$_{1.6-x}$Nd$_{0.4}$Sr$_x$CuO$_4$ was measured down to 50 mK in seven crystals with doping from $p=0.12$ to $p=0.24$, both in the superconducting state and in the magnetic field-induced normal state. We obtain the electronic residual linear term $\kappa_0$ as $T \to 0$ across the pse...
Preprint
The perfectly linear temperature dependence of the electrical resistivity observed as $T \rightarrow$ 0 in a variety of metals close to a quantum critical point is a major puzzle of condensed matter physics . Here we show that $T$-linear resistivity as $T \rightarrow$ 0 is a generic property of cuprates, associated with a universal scattering rate....
Article
Full-text available
The properties of cuprate high-temperature superconductors are largely shaped by competing phases whose nature is often a mystery. Chiefly among them is the pseudogap phase, which sets in at a doping p* that is material-dependent. What determines p* is currently an open question. Here we show that the pseudogap cannot open on an electron-like Fermi...
Article
Full-text available
The thermal conductivity $\kappa$ of the Kondo insulator SmB$_6$ was measured at low temperature, down to 70~mK, in magnetic fields up to 15~T, on single crystals grown using the floating-zone method. The residual linear term $\kappa_0/T$ at $T \to 0$ is found to be zero in all samples, for all magnetic fields, in agreement with a previous study. T...
Article
The electrical resistivity ρ and Hall coefficient RH of the tetragonal single-layer cuprate La1.6-xNd0.4SrxCuO4 were measured in magnetic fields up to H=37.5 T, large enough to access the normal state at T→0, for closely spaced dopings p across the pseudogap critical point at p=0.23. Below p, both coefficients exhibit an upturn at low temperature,...
Article
Full-text available
The Seebeck coefficient $S$ of the cuprate YBa$_{2}$Cu$_{3}$O$_{y}$ was measured in magnetic fields large enough to suppress superconductivity, at hole dopings $p = 0.11$ and $p = 0.12$, for heat currents along the $a$ and $b$ directions of the orthorhombic crystal structure. For both directions, $S/T$ decreases and becomes negative at low temperat...
Article
We use the Nernst effect to delineate the boundary of the pseudogap phase in the temperature-doping phase diagram of cuprate superconductors. New data for the Nernst coefficient $\nu(T)$ of YBa$_{2}$Cu$_{3}$O$_{y}$ (YBCO), La$_{1.8-x}$Eu$_{0.2}$Sr$_x$CuO$_4$ (Eu-LSCO) and La$_{1.6-x}$Nd$_{0.4}$Sr$_x$CuO$_4$ (Nd-LSCO) are presented and compared with...
Article
The thermal conductivity κ of the iron-based superconductor FeSe was measured at temperatures down to 75 mK in magnetic fields up to 17 T. In a zero magnetic field, the electronic residual linear term in the T=0 K limit, κ0/T, is vanishingly small. The application of a magnetic field B causes an exponential increase in κ0/T initially. Those two obs...
Article
The electrical resistivity $\rho$ and Hall coefficient R$_H$ of the tetragonal single-layer cuprate Nd-LSCO were measured in magnetic fields up to $H = 37.5$ T, large enough to access the normal state at $T \to 0$, for closely spaced dopings $p$ across the pseudogap critical point at $p^\star = 0.235$. Below $p^\star$, both coefficients exhibit an...
Article
Full-text available
There is strong experimental evidence that the superconductor Sr2RuO4 has a chiral p-wave order parameter. This symmetry does not require that the associated gap has nodes, yet specific heat, ultrasound and thermal conductivity measurements indicate the presence of nodes in the superconducting gap structure of Sr2RuO4. Theoretical scenarios have be...
Article
Superconductivity in cuprates peaks in the doping regime between a metal at high p and an insulator at low p. Understanding how the material evolves from metal to insulator is a fundamental and open question. Early studies in high magnetic fields revealed that below some critical doping an insulator-like upturn appears in the resistivity of cuprate...